Use of Frozen Embryos Tied to Higher Odds for Dangerous Complication of Pregnancy

Frozen embryos appear to be linked with a significantly higher risk of dangerouslyhigh blood pressurefor the woman inpregnanciesachieved throughin vitro fertilization, a major new study reports.

Expectant moms were 74% more likely to develophigh blood pressureif herpregnancyresulted from a frozen embryo, as opposed to a fresh embryo or naturalconception, according to analysis of more than 4.5 millionpregnancies.

这些结果可能标志着一个巨大变化的方式ssisted reproduction is performed, researchers said.

"Frozen embryo transfers are now increasingly common all over the world, and in the last few years, some doctors have begun skipping fresh embryo transfer to routinely freeze all embryos in their clinical practice, the so-called 'freeze-all' approach," said lead researcher Dr. Sindre Petersen, a doctoral fellow at the Norwegian University of Science and Technology in Trondheim.

"Our results highlight that careful consideration of all benefits and potential risks is needed before freezing all embryos as a routine in clinical practice," he added. "A comprehensive, individualized conversation between physicians and patients about the benefits and risks of a fresh vs. frozen embryo transfer is key."

For the study, published Sept. 26 in高血压, a journal of the AmericanHeartAssociation, the researchers reviewed the medical data of nearly 2.4 million women from Denmark, Norway and Sweden who had one or more single deliveries between 1988 and 2015. The women ranged in age from 20 to 44.

Of the more than 4.5 million pregnancies identified, 4.4 million were naturally conceived. More than 78,000 involved fresh embryo transfers, while more than 18,000 involved frozen embryos.

High blood pressureduringpregnancyoften signalspreeclampsia, a complication that can endanger both the mother and the fetus.Preeclampsiaaffects about 1 in every 25 U.S. pregnancies, according to the AmericanHeartAssociation.

Researchers reviewed medical records forpreeclampsiaand other conditions related tohigh blood pressureduringpregnancy. These included gestational high官网地址bwin, chronichigh blood pressurewith superimposedpreeclampsia, andeclampsia, the onset ofseizuresin women with preeclampsia.

They particularly zeroed in on 33,000 pregnancies in which a woman had conceived by more than one method, which allowed the team to compare siblings.

Researchers found a woman's risk of ahigh blood pressuredisorder doubled when she received a frozen embryo duringIVF, compared to when the same woman conceived a sibling naturally.

Risk was no higher with the use of fresh embryos compared to naturalconceptionin women who gotpregnantboth ways.

"Our sibling comparisons indicate that the higher risk is not caused by factors related to the parents, rather, however, that someIVFtreatment factors may be involved," Petersen said in a journal news release. "Future research should investigate which parts of the frozen embryo transfer process may impact risk ofhypertensionduringpregnancy."

More information

The Mayo Clinic has more about in vitrofertilization.

SOURCE: American Heart Association, news release, Sept. 26, 2022

By Dennis Thompson HealthDay Reporter

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